You can destroy a hdd remotely but I'd say the chances of a your friend
running into somebody that knew how and having nothing better to do fairly
remote. What kind of drive is it? If he boots from a clean non-WinNT boot
floppy does the hdd show up okay? If the data on the hdd is all lost
anyway I'd try throwing in a Linux installation cd and seeing if it can
work with the hdd okay. Apart from that you should try it in another
machine to make sure his BIOS wasn't somehow fried to not detect the hdd.

> A friend says he had a hacker destroy his HDD. I told him that is not
> possible.
> He has tried zeroing out the drive and even performed a low level
> format. It was running
>  NT 4, he thinks. This means he had some software running as a disk
> manager showing NT
> what it wanted to see. I am convinced, that it is not possible to
> destroy a HDD remotely.
> BIOS yes. Firmware yes, if it if eeprom/flash. Can anyone prove me
> wrong?